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Resistance Characteristics of Hydraulic Oil through Isodiametric T-type Duct with Sharp Corners

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Chinese Journal of mechanical engineering 2009年第2期22卷 250-255页

作者： tang jinglin WANG Liwei LI Xia college of mechanical engineering Yanshan University Qinhuangdao 066004 China Taiyuan Heavy Mechinery Group Taiyuan 030024 China

Rational determination and reduction of local energy loss of oil flow at pipe junctions are of important significance to improve hydraulic pipeline＇s work efficiency, especially for complex hydraulic pipeline connected by isodiametric T-type ducts with sharp comers to get combined and divided flow. From this point of view, the formulae of resistance loss for combined flow and divided flow through isodiametric T-type duct with sharp comers as well as the correlations of resistance loss coefficients in the branches of the duct are derived using energy method. On this basis, resistance characteristics of hydraulic oil in the duct are obtained by numerical simulation of different flow modes, which are commonly applied in hydraulic pipelines, using computational fluid dynamics （CFD） method, and the reasons for the resistance loss are analyzed based on the pressure change mechanism in the flow field. A part of simulation results was validated with the reference data. The research shows that for combined flows the resistance loss of symmetrical is lower than that of unsymmetrical to obtain low speed in common branch, but to gain high speed is quite the contrary, for divided flows, the symmetrical is always a reasonable choice to reduce resistance loss. These conclusions can be applied to optimize the design of hydraulic pipeline.

关键词： hydraulic oil T-type duct energy method computational fluid dynamics (CFD) resistance characteristic

马氏体时效钢激光选区熔化成形过程介观尺度数值模拟

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机械工程学报 2024年第3期60卷 282-295页

作者：宋军唐倩罗智超冯琪翔聂云飞任治好重庆大学机械与运载工程学院重庆400044 华中科技大学材料成形与模具技术全国重点实验室武汉430074 重庆邮电大学先进制造工程学院重庆400065

激光选区熔化(Selective laser melting,SLM)成形过程涉及多种发生于介观尺度下的物理现象,采用试验方法难以揭示物理现象复杂的形成规律。以18Ni-3.0马氏体时效钢为SLM成形材料,采用离散元法与有限体积法建立了SLM成形介观尺度热流耦... 详细信息

激光选区熔化(Selective laser melting,SLM)成形过程涉及多种发生于介观尺度下的物理现象,采用试验方法难以揭示物理现象复杂的形成规律。以18Ni-3.0马氏体时效钢为SLM成形材料,采用离散元法与有限体积法建立了SLM成形介观尺度热流耦合数值模型,并结合熔道成形试验验证模型的正确性。结合数值模拟揭示激光功率从60 W增加至270 W时单道SLM成形熔道形貌、熔池尺寸与温度、传热机制等熔池行为的基本特征;研究在0.2 J/mm、0.3.J/mm和0.45 J/mm线能量密度下不同激光功率和扫描速度组合对熔道形貌、熔池尺寸与传热机制的影响规律;结合熔道搭接理论模型计算激光功率180 W和扫描速度600 mm/s组合下无搭接缺陷的扫描间距理论临界条件约为83.m,并研究80μm、100μm和120μm扫描间距下多道多层SLM成形熔道搭接行为和演变规律。该模型可用于筛选工艺参数区间,提高工艺优化效率,为单层/多层成形的工艺试验提供指导。

关键词：激光选区熔化马氏体时效钢数值模拟熔池缺陷

基于力控技术的航空整体加强框自适应定位方法研究

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机械设计与制造 2024年第4期398卷 225-228,233页

作者：于鑫武锋锋聂勇唐文献太原理工大学机械与运载工程学院山西太原030024 太原理工大学航空航天学院山西晋中030600

为了减弱制造差异对航空整体加强框装配定位质量的影响,解决强迫定位造成的定位过程管控性差和定位结果复现度低的难题,基于力控技术提出一种航空整体加强框自适应定位方法,按传统强迫方式完成装配定位后,在设计允许范围内调整若干坐标... 详细信息

为了减弱制造差异对航空整体加强框装配定位质量的影响,解决强迫定位造成的定位过程管控性差和定位结果复现度低的难题,基于力控技术提出一种航空整体加强框自适应定位方法,按传统强迫方式完成装配定位后,在设计允许范围内调整若干坐标定位孔位置,至孔位处力载值满足自适应定位要求。针对航空整体加强框装配定位工艺对形位精度、装配应力水平的要求,量化装配定位质量评价标准,基于正交试验分析定位孔处力载绝对平均值和定位检测点处应力绝对平均值的变化规律,进行装配现场易于获取的力载值取代应力值的可行性研究,通过修正装配定位质量评价标准量化公式得到坐标定位孔处力载调整目标,指导航空整体加强框装配定位。

关键词：整体加强框力控装配定位自适应孔位

Microstructure and mechanical properties of Al-Mg-Mn alloy with erbium

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Rare Metals 2012年第3期31卷 237-243页

作者： Wang, Xudong Lin, Shuangping Yang, Junjun tang, Zhenlei nie, Zuoren School of mechanical engineering Taiyuan University of Technology Taiyuan 030024 China Metal Working engineering Department China Iron and Steel Research Insititute Group Beijing 100081 China Nonferous Metals Processing Division General Research Institute of Nonferrous Metal Beijing 100088 China college of Materials Science and engineering Beijing University of Technology Beijing 100124 China

The effect of trace element Er on the microstructure and properties of Al-6Mg-0.7Mn-0.1Cr-0.15Ti alloy was investigated. The results show that the ultimate room-temperature and high-temperature strength sof the alloy have not increased obviously with the addition of erbium, but the uniform elongation of alloys decreases from 9% and 27.5% to 5.5% and 22.5%, respectively. The reason is that the addition of Er will first react with Ti, Cr to form Al20Ti2Er, Al8Cr4Er phases. The precipitation strengthening makes up the weakening of grain refinement strengthening. During deformation, the primary Al(TiCr)Er and Al3.r particles fracture first and act as the microcrack sources because of the stress concentration.

关键词： Al-Mg-Mn alloy erbium microstructure mechanical properties

Lifetime and Aging Degradation Prognostics for Lithium-ion Battery Packs Based on a Cell to Pack Method

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Chinese Journal of mechanical engineering 2022年第1期35卷 192-207页

作者： Yunhong Che Zhongwei Deng Xiaolin tang Xianke Lin Xianghong nie Xiaosong Hu college of mechanical and Vehicle engineering Chongqing UniversityChongqing 400044China State Key Laboratory of mechanical Transmissions Chongqing UniversityChongqing 400044China Department of Automotive Mechanical and Manufacturing EngineeringOntario Tech UniversityOshawaON L1G 0C5Canada Powertrain engineering R&D Institute Chongqing Changan Automotive Co.LtdChongqing 401133China

Aging diagnosis of batteries is essential to ensure that the energy storage systems operate within a safe *** paper proposes a novel cell to pack health and lifetime prognostics method based on the combination of transferred deep learning and Gaussian process *** health indicators are extracted from the partial discharge *** sequential degradation model of the health indicator is developed based on a deep learning framework and is migrated for the battery pack degradation *** future degraded capacities of both battery pack and each battery cell are probabilistically predicted to provide a comprehensive lifetime ***,only a few separate battery cells in the source domain and early data of battery packs in the target domain are needed for model *** results show that the lifetime prediction errors are less than 25 cycles for the battery pack,even with only 50 cycles for model fine-tuning,which can save about 90%time for the aging ***,it largely reduces the time and labor for battery pack *** predicted capacity trends of the battery cells connected in the battery pack accurately reflect the actual degradation of each battery cell,which can reveal the weakest cell for maintenance in advance.

关键词： Lithium-ion battery packs Lifetime prediction Degradation prognostic Model migration Machine learning

Optimisation of alloy composition for highly-formable magnesium sheet

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International Journal of Minerals,Metallurgy and Materials 2022年第7期29卷 1388-1395页

作者： Zhuoran Zeng Mingzhe Bian Shiwei Xu Weineng tang Chris Davies Nick Birbilis Jianfeng nie college of engineering and Computer Science Australian National UniversityACT.2601Australia Department of Materials Science and engineering Monash UniversityVIC 3800Australia State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China Research Institute(R&D Center) Baosteel Group CorporationShanghai 201999China Department of mechanical and Aerospace engineering Monash UniversityVIC 3800Australia

The effectiveness of Ca or Gd addition on ductility and formability of Mg-Zn-Zr based dilute alloys in deep drawing has not been systematically compared *** this study,formable Mg-Zn-Gd-Zr and Mg-Zn-Ca-Zr sheet alloys are produced by hot *** sheets have similarly weakened basal texture,but the sheet of the Mg-Zn-Gd-Zr alloys has higher ductility and formability than that of Mg-Zn-Ca-Zr *** combined addition of 0.2wt%Ca and 0.4wt%Gd to the Mg-1Zn-0.5Zr(wt%)alloy leads to a Mg-1Zn-0.4Gd-0.2Ca-0.5Zr alloy that has even better ductility,and its formability during deep drawing is comparable to the benchmark Al6016 *** increase in Ca content from 0.2wt%to 0.5wt%leads to decreased sheet ductility and formability,predominantly due to grain boundary embrittlement.

关键词： magnesium sheet alloy texture microstructure formability solute segregation

轴承不对中-碰摩耦合故障下双转子系统非线性振动特性分析

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机械强度 2024年第3期46卷 518-526页

作者：聂彦春蔚建辉张雷克王雪妮张金剑唐华林山西中部引黄工程建设管理有限公司太原030024 太原理工大学水利科学与工程学院太原030024 大连理工大学水利电力研究所大连116023 中国水利水电开发有限公司成都610000

为揭示因轴承不对中导致的故障转子系统振动特性,基于坐标变换关系,推导了轴承不对中下转子偏转位移表达式。在此基础上,建立了综合考虑碰摩力、油膜力等外激励影响下双盘转子轴承不对中-碰摩耦合故障系统动力学模型,采用数值方法研究... 详细信息

为揭示因轴承不对中导致的故障转子系统振动特性,基于坐标变换关系,推导了轴承不对中下转子偏转位移表达式。在此基础上,建立了综合考虑碰摩力、油膜力等外激励影响下双盘转子轴承不对中-碰摩耦合故障系统动力学模型,采用数值方法研究了转速及质量偏心对系统动态特性的影响。结果表明,轴承不对中故障会增加系统碰摩发生可能性、恶化轴系振动并加大系统非稳态运动范围。虽然不对中量的加入可在一定程度上延缓系统因参数变化引起的失稳运动,但据此产生的振幅增加与系统安全运行目标相悖,故应采取必要措施对轴承不对中故障加以控制。相关结论可为转子-轴承系统振动状态识别及稳定性分析提供有益借鉴。

关键词：转子-轴承系统轴承不对中碰摩偏转

热处理对选区激光熔化制备的点阵结构性能影响研究

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航空制造技术 2024年第3期67卷 45-54页

作者：聂云飞唐倩李坤王浩宇吴海斌王彬生秦昌亮杨震石佳重庆大学机械与运载工程学院重庆400044 金属增材制造(3.打印)重庆市重点实验室重庆400044 高端装备机械传动全国重点实验室重庆400044 国家能源集团神东煤炭集团有限责任公司鄂尔多斯017200 重庆齿轮箱有限责任公司重庆402263

选区激光熔化(SLM)技术因其独特的成形原理成为制备复杂点阵结构的理想工艺。以钛合金骨架和片状结构为研究对象,通过数值仿真和试验相结合的方法,分析了热处理工艺对结构微观组织、力学性能、断裂机制及吸能特性的影响规律。结果表明,... 详细信息

选区激光熔化(SLM)技术因其独特的成形原理成为制备复杂点阵结构的理想工艺。以钛合金骨架和片状结构为研究对象,通过数值仿真和试验相结合的方法,分析了热处理工艺对结构微观组织、力学性能、断裂机制及吸能特性的影响规律。结果表明,固溶时效热处理后钛合金中α+β相均匀分布,固溶温度的增加会使片状α'相马氏体逐渐减少而β相增多;不同热处理状态下片状结构压缩强度为骨架结构的1.81~2.17倍,平台应力为后者的3.1倍,但两者弹性模量相当,同时热处理工艺对骨架结构力学性能影响较小而对片状结构影响较大;两类结构都表现出了45°结对角剪切断裂和断裂带传递的现象;骨架结构能量吸收效率远大于片状结构,但累积能量吸收量较低,热处理工艺没有提高被测结构的吸能性能。

关键词：选区激光熔化(SLM) 点阵结构热处理力学性能断裂机制吸能性能

Study on Wheel and Workpiece Position Error Influence on Surface Shape Accuracy during Ceramic Ball Grinding

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Journal of Harbin Institute of Technology(New Series) 2013年第4期20卷 31-35页

作者： Feng-Ming nie Zhan-Guo Li Qing-tang Wu Huan Wu Shan Li Bo Guo mechanical and Electrical engineering college Changchun University of Science and Technology Lab of Ultra-precision Fabrication Changchun Institute of Equipment and Process The Principal's Office Changchun University

The reasons for bringing surface accuracy error in ultra-precision grinding ceramic ball joint were analyzed,and the influences wheel position error and shaft run-out error on the ball joint surface accuracy were *** establishing three-dimensional grinding model,the mathematical relationship between the position error and surface accuracy was derived,and the distance from any point on spherical surface to the ideal center was calculated when position error existed,and a precise surface shape was got,and theoretical support was provided to improve the surface accuracy during the grinding *** self-developed ultraprecision grinding machine to do the ceramic ball grinding experiment,the surface accuracy PV value of ceramic spherical joint is 4.8μm.

关键词： precision grinding error analysis surface accuracy ball joint